Oahe Dam Tail Race

Oahe Dam Tail Race below Oahe Dam on the Missouri River near Pierre, South Dakota, offers intermediate freshwater divers an unusual diving opportunity in the tailwaters of one of the Missouri River system's largest dams—cold, clear water released from deep within the reservoir emerging into the river channel below the dam in conditions that create a distinct and productive freshwater diving environment. The Oahe Dam, completed in 1962, impounds Lake Oahe—one of the largest man-made lakes in the United States by volume—releasing its hypolimnetic water through the dam's powerhouse into the river below at temperatures that remain consistently cold year-round, a characteristic that sustains the trout fishery that the tailrace is famous for. The tailrace environment below Oahe Dam creates diving conditions fundamentally different from the lake diving typical of South Dakota's freshwater resources. Cold, oxygenated water released from depth carries the clarity of hypolimnetic water—the deep, still layer of the reservoir where particulates settle and the water achieves maximum transparency—into the river channel below the dam. This cold, clear water sustains rainbow trout in a fishery that attracts anglers from considerable distances to the Missouri River below Pierre, and the same conditions that make the tailrace a premium trout fishery make it an interesting freshwater dive environment. Rainbow trout in tailrace environments adapt to the flowing current with the precision of fish that have optimized their position in the water column relative to available current speed and food delivery. Observing these fish from underwater in the clear tailrace water—their spotted sides visible in full detail, their fins making constant micro-adjustments to hold station in the current—is a freshwater fish encounter of unusual quality. The clarity of tailrace water allows trout observation from distances that turbid river water prevents, creating the extended encounter quality that productive freshwater wildlife diving requires. Navigating the current that defines tailrace diving is the primary challenge that earns Oahe an intermediate rating. Tailwater current—significant but more consistent than natural flood-driven river conditions—requires steady swimming and positional awareness that exceeds the demands of still-water lake or quarry diving. Understanding how to use current shadow zones, how to position relative to bottom structure, and how to plan gas consumption for a current-modified dive profile are all skills that tailrace diving develops and that transfer usefully to other moving-water environments. South Dakota's landscape along the Missouri River above and below Oahe Dam—the rolling prairie, the river cottonwoods, the broad Missouri channel—creates a distinctly Great Plains freshwater diving context unlike anything available in the Midwest's forested lake country or the Rocky Mountain region's alpine settings. Diving below Oahe Dam connects divers to the Missouri River system's magnificent scale and to the engineering achievement that transformed the river into the series of managed reservoirs that today define South Dakota's freshwater landscape.